// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/base/io_buffer.h"

#include "base/logging.h"
#include "base/numerics/safe_math.h"

namespace net {

namespace {

    // TODO(eroman): IOBuffer is being converted to require buffer sizes and offsets
    // be specified as "size_t" rather than "int" (crbug.com/488553). To facilitate
    // this move (since LOTS of code needs to be updated), both "size_t" and "int
    // are being accepted. When using "size_t" this function ensures that it can be
    // safely converted to an "int" without truncation.
    void AssertValidBufferSize(size_t size)
    {
        base::CheckedNumeric<int>(size).ValueOrDie();
    }

    void AssertValidBufferSize(int size)
    {
        CHECK_GE(size, 0);
    }

} // namespace

IOBuffer::IOBuffer()
    : data_(NULL)
{
}

IOBuffer::IOBuffer(int buffer_size)
{
    AssertValidBufferSize(buffer_size);
    data_ = new char[buffer_size];
}

IOBuffer::IOBuffer(size_t buffer_size)
{
    AssertValidBufferSize(buffer_size);
    data_ = new char[buffer_size];
}

IOBuffer::IOBuffer(char* data)
    : data_(data)
{
}

IOBuffer::~IOBuffer()
{
    delete[] data_;
    data_ = NULL;
}

IOBufferWithSize::IOBufferWithSize(int size)
    : IOBuffer(size)
    , size_(size)
{
    AssertValidBufferSize(size);
}

IOBufferWithSize::IOBufferWithSize(size_t size)
    : IOBuffer(size)
    , size_(size)
{
    // Note: Size check is done in superclass' constructor.
}

IOBufferWithSize::IOBufferWithSize(char* data, int size)
    : IOBuffer(data)
    , size_(size)
{
    AssertValidBufferSize(size);
}

IOBufferWithSize::IOBufferWithSize(char* data, size_t size)
    : IOBuffer(data)
    , size_(size)
{
    AssertValidBufferSize(size);
}

IOBufferWithSize::~IOBufferWithSize()
{
}

StringIOBuffer::StringIOBuffer(const std::string& s)
    : IOBuffer(static_cast<char*>(NULL))
    , string_data_(s)
{
    AssertValidBufferSize(s.size());
    data_ = const_cast<char*>(string_data_.data());
}

StringIOBuffer::StringIOBuffer(std::unique_ptr<std::string> s)
    : IOBuffer(static_cast<char*>(NULL))
{
    AssertValidBufferSize(s->size());
    string_data_.swap(*s.get());
    data_ = const_cast<char*>(string_data_.data());
}

StringIOBuffer::~StringIOBuffer()
{
    // We haven't allocated the buffer, so remove it before the base class
    // destructor tries to delete[] it.
    data_ = NULL;
}

DrainableIOBuffer::DrainableIOBuffer(IOBuffer* base, int size)
    : IOBuffer(base->data())
    , base_(base)
    , size_(size)
    , used_(0)
{
    AssertValidBufferSize(size);
}

DrainableIOBuffer::DrainableIOBuffer(IOBuffer* base, size_t size)
    : IOBuffer(base->data())
    , base_(base)
    , size_(size)
    , used_(0)
{
    AssertValidBufferSize(size);
}

void DrainableIOBuffer::DidConsume(int bytes)
{
    SetOffset(used_ + bytes);
}

int DrainableIOBuffer::BytesRemaining() const
{
    return size_ - used_;
}

// Returns the number of consumed bytes.
int DrainableIOBuffer::BytesConsumed() const
{
    return used_;
}

void DrainableIOBuffer::SetOffset(int bytes)
{
    DCHECK_GE(bytes, 0);
    DCHECK_LE(bytes, size_);
    used_ = bytes;
    data_ = base_->data() + used_;
}

DrainableIOBuffer::~DrainableIOBuffer()
{
    // The buffer is owned by the |base_| instance.
    data_ = NULL;
}

GrowableIOBuffer::GrowableIOBuffer()
    : IOBuffer()
    , capacity_(0)
    , offset_(0)
{
}

void GrowableIOBuffer::SetCapacity(int capacity)
{
    DCHECK_GE(capacity, 0);
    // realloc will crash if it fails.
    real_data_.reset(static_cast<char*>(realloc(real_data_.release(), capacity)));
    capacity_ = capacity;
    if (offset_ > capacity)
        set_offset(capacity);
    else
        set_offset(offset_); // The pointer may have changed.
}

void GrowableIOBuffer::set_offset(int offset)
{
    DCHECK_GE(offset, 0);
    DCHECK_LE(offset, capacity_);
    offset_ = offset;
    data_ = real_data_.get() + offset;
}

int GrowableIOBuffer::RemainingCapacity()
{
    return capacity_ - offset_;
}

char* GrowableIOBuffer::StartOfBuffer()
{
    return real_data_.get();
}

GrowableIOBuffer::~GrowableIOBuffer()
{
    data_ = NULL;
}

PickledIOBuffer::PickledIOBuffer()
    : IOBuffer()
{
}

void PickledIOBuffer::Done()
{
    data_ = const_cast<char*>(static_cast<const char*>(pickle_.data()));
}

PickledIOBuffer::~PickledIOBuffer()
{
    data_ = NULL;
}

WrappedIOBuffer::WrappedIOBuffer(const char* data)
    : IOBuffer(const_cast<char*>(data))
{
}

WrappedIOBuffer::~WrappedIOBuffer()
{
    data_ = NULL;
}

} // namespace net
